Easy opening structure for drumhead carton

ABSTRACT

The disclosure herein relates to a tear opening arrangement for end filled, end sealed cartons and, more specifically, to an improved tear opening structure for membrane sealed rectangular parallelpiped cartons of the type in which a separate safety shield material of polyethylene coated glassine polyester film or the like is heat sealed or otherwise tightly sealed to the four end closing flaps of the carton. Simple and improved corner opening is achieved by the provision of a special lift tab and severable dust flap which cooperate through the interposed membrane.

United States Patent [191 Young et al.

[ EASY OPENING STRUCTURE FOR DRUMHEAD CARTON [75] Inventors: Chauncey Young; William H.

I Y Watson, both of St. Louis, Mo.

[73] Assignee: Rexham Corporation, New York,

22 Filed: Jan. 14,1971 21 Appl. No. 106,525

[52] US. Cl 229/17 R 51 Int. c|.., B65d 5/72 58] Field of Search 229/17 R [56] i References Cited v UNITED STATES PATENTS 3,498,522 3/1970 Peet 229/17 R 2,946,496 7/1960 Stagrneier 229/17 R 3,180,553 4/1965 Schreiber et al.... 229/17 R 3,136,471 6/1964- Brastad 229/17R Olson..... 229/17 R 2,364,364 12/1944 Hultin 229/17 R FOREIGN PATENTS OR APPLICATIONS 34,135 1965 Finland 229/17 R Primary Examiner-Allen N. Knowles Attorney-Mandeville & Schweitzer 57 ABSTRACT The disclosure herein relates to a tear opening arrangement for end filled, end sealed cartons and, more specifically, to an improved tear opening structure for membrane sealed rectangular parallelpiped cartons of the type in which a separate safety shield material of polyethylene coated glassine polyester film or the like is heat sealed or otherwise tightly sealed to the four end closing flaps of the carton. Simple and improved corner opening is achieved by the provision of a special lift tab and severable'dust flap which cooperate through the interposed membrane. 7

4 Claims, 5 Drawing Figures EASY OPENING STRUCTURE FOR DRUMHEAD CARTON BACKGROUND OF THE INVENTION Many airtight, siftproof and moistureproof paperboard carton constructions for liquid and pulverulent materials are formed from parallelpiped cartons and have their opposite ends tightly sealed by the safety shield members or membranes adhered to the major and minor carton end flaps, i.e., the end flaps and the dust flaps. The membrane material and/or the inner surfaces of the end closing flaps to which they are adhered are thermoplastic. For example, if a paper machine is employed, a resin, a wax, or other material which may be easily heat sealed may be coated thereon. The moistureproofness and siftproofness of such cartons is often enhanced by the formation of special corner structures in the carton before the membrane is sealed to the flaps.

With the development of improved coated and laminated paperboard materials and improved thermoplastic films, the tightness and imperviousness of membrane sealed cartons of the aforementioned type have been greatly improved, and these cartons have continued to find ever increasing acceptance and widespread use in diverse packaging applications. However, the improved strengths of the heat seal bonds of the membrane tothe carton flaps have often introduced serious opening problems for the ultimate consumer. Accordingly, it is to one solution of these opening problems that the present invention is directed.

SUMMARY OF THE INVENTION In accordance with the principles of the present invention, a unique corner opening for a drumhead carton is provided by forming a removable lift-starting tab at one of the corners of the outer major end flap of the drumhead carton; making the immediately adjacent dust flap severable or partially severable from the carton by means of tear line; and by tapering or otherwise appropriately shaping the end edge of the inner major flap, which overlies the removable dust flap and underlies the outermost major flap.

With the corner opening .construction of the invention, simple and rapid access to the contents of the carton is readily attained. Moreover, the new corner dispensing opening may be established by a user by merely grasping the special lift tab, pivoting it into a vertical position with respect to the sealed end of the carton, and finally, using the lift tab as a lever, separating the lift tab from the carton edge and tearing the dust flap from the end edge along the tear line thereby effectively peeling back" the folded membrane without the necessity of breaking the tight membrane to paperboard bond.

DESCRIPTION OF THE DRAWING For a better understanding of the present invention and its attendant advantages, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a fragmentary plan elevational view of a carton blank from which a carton embodying the principles of the invention may be fabricated;

FIG. 2 is a fragmentary perspective view of the carton of the present invention, with the end closing flaps out folded and with the safety shield applied and bonded thereto;

FIG. 3 is a fragmentary perspective view of the completed new carton showing the end flaps infolded;

FIG. 4 is a fragmentary perspective view of the new carton with the lift tab severedfrom the. remainder of the outer major flap, but not otherwise removed from the carton during the first step of carton opening; and

FIG. 5 is a fragmentary perspective view of the carton showing the lift tab severed from the carton tube, the adjacent dust flap partially severed from the carton, and the new dispensing opening established at a carton corner.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring to FIG. 1, the new tear opening structure 7 of the invention is embodied in a drumhead carton blank 10. While only the upper portions of the blank 10 are illustrated, it should be understood that the lower portions may be identical to the upper portions when it is desired tohave a drumhead carton which may be opened from either end. Alternatively, thje lower portions of the blank 10 may be conventional (four end closing flaps and a glue flap).

More specifically, the carton blank 10 includes a first side wall panel 11, a rear wall panel 12, a second side wall panel 13, a front wall panel 14 and a glue flap panel 15 consecutively articulated along vertical score lines 16-19, respectively. A conventional dust flap (minor flap) 20 is articulated to the side panel 11 along a horizontal score line 21. An inner end flap (major flap) 22 is articulated to the rear wall 12 along a horizontal score line 23, which is colinear with the score line 21 and definitive of the upper edge of the carton, as will be understood. A second dust flapi 23 is articulated to the second side wall panel 13 along a line of weakness 24, comprised of a series of cut scores, which do not completely penetrate the blank material (thereby not interfering with the impermeability of the finished container).

In accordance with the invention, the outer end flap 25 of the carton is divided into a pair of elements, a lift tab 26 and an end flap segment 27, separated from one another by a vertical line of weakness 28 formed of a series of cut scores. Advantageously, and as shown, the outer edge of the lift tab 26 is of arcuate configuration for ease of manual grasping and for indication of its special function. The. lift tab 26 is articulated to the edge of the wall panel 14, immediately adjacent to the dust flap-23 by a line of weakness 29 comprised by a series of cut scores, which are colinear with the cut scores 24. The end flap segment 27 is articulated by a horizontal score line 3010 the wall panel 14 and a glue flap extension 31 is articulated to the glue flap 15 by an extension of the score line 30.

The blank 10 may be formed into a drumhead carton by conventional techniques. Thus, it is first formed into a carton tube by the adhering of the glue flap 15 and its extension 31 to the first side panel 11 and its contiguous dust flaps. Thereafter, the carton tube is squared, the end closing flaps are outfolded; and a safety shield or membrane material '32is heat sealed or 0therwise adhesively secured to the outfolded flaps along narrow sealing zones 33 adjacent each of the carton tearable, as is the case for example with polyethylene terephalate (Mylar), a V-shaped notch 34 is provided at the edge to facilitate tearing of the film as shown in FIG. 2. This starting notch is disposed just beyond the sealing zone 33 and in straddling relation to the line of weakness 38. Of course, when a readily tearable material is employed, such as coated glassine or a weak plastic film, it is not necessary to employ the starting notch 34. After the membrane has been sealed to the outfolded carton flaps as shown in FIG. 2, the minor flaps 20, 23 are infolded. Then, the inner end flap 22 is infolded, and, finally, the outer end flap 25 is infolded and secured to the underlying flap 22 by a suitable adhesive or the like disposed between the flap segment 27 and the underlying end flap 22. In this manner, the lift tab is not glued or sealed to the flap 22, and it is there- 'fore readily tearable. The completed end structure of the invention is shown in FIG. 3.

Opening of the drumhead carton of the invention, is quick and simple. The user merely grasps the lift tab 26 and pivots into a vertical position (FIG. 4) thereby severing the tab 26 from the end flap segment 27 and tearing the membrane 32. Then the tab 27 is pulled upwardly and toward the diagonally opposite corner of the carton. This effects a lever-like action which easily severs the dust flap 23 along the tear line 24 and folds back the membrane 32 against the oblique edge 22 of the flap 22 to expose a corner, dispensing opening 35 (FIG. It will be appreciated, that the folded membrane 32, itself, links the tab 26 and dust flap 23, which are otherwise independent.

It is to be understood that the specific embodiment of the drumhead carton herein described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

We claim 1. ha blank for a drumhead carton, including first side wall, rear wall, second side wall, front wall, and glue flap panels consecutively articulated along parallel vertical score lines, and bottom closing flaps articulated to the lower edges of said walls, an improved tear opening structure comprising,

a. first and second dust flaps articulated to each of said side wall panels along lines of weakness;

b. front and rear end flaps articulated to said front and rear wall panels, respectively, along lines of weakness;

c. said second dust flap being disposed between said end flaps;

d. said rear end flap being of substantially less than full carton width adjacent said second dust flap; e. said rear end flap having an oblique edge sloping toward said second dust flap;

f. said front end fiap having a severable lift tab formed therein immediately adjacent to said second dust flap;

g. the edge of said lift tab being defined by at least two tear lines, one of which extends to the other mentioned tear line.

2. The blank of claim 1, in which a. said lift tab has a generally arcuate free edge.

3. An easy opening drumhead carton including a. consecutively articulated first side, rear, second side, and front walls;

b. dust flaps articulated to the ends of said side walls;

0. major end closing flaps articulated to the ends of said front and rear walls;

d. one of said dust flaps being articulated along a tearable weakened line;

e. a major flap adjacent to said one dust flap having a severable lift tab formed therein by a tear line transversely dividing said flap;

f. a sealing membrane adhered along narrow sealing zones to said dust flaps and said major end flaps; g. an edge of said membrane defining a notch beyond said sealing zone, said notch being superimposed upon said transverse tear line;

h. said dust flaps being first infolded and underlying said major flaps; and

i. said divided major flap being the outermost flap.

4. The carton of claim 3, in which a. said major flaps are of less than full carton depth.

* l I t 

2. The blank of claim 1, in which a. said lift tab has a generally arcuate free edge.
 3. An easy opening drumhead carton including a. consecutively articulated first side, rear, second side, and front walls; b. dust flaps articulated to the ends of said side walls; c. major end closing flaps articulated to the ends of said front and rear walls; d. one of said dust flaps being articulated along a tearable weakened line; e. a major flap adjacent to said one dust flap having a severable lift tab formed therein by a tear line transversely dividing said flap; f. a sealing membrane adhered along narrow sealing zones to said dust flaps and said major end flaps; g. an edge of said membrane defining a notch beyond said sealing zone, said notch being superimposed upon said transverse tear line; h. said dust flaps being first infolded and underlying said major flaps; and i. said divided major flap being the outermost flap.
 4. The carton of claim 3, in which a. said major flaps are of less than full carton depth. 